michel2k

From the page: "IP warming is a gradual process that happens over time, with the goal of establishing a reputation as a legitimate email sender in the eyes of ISPs (Internet Service Providers). When an ISP observes email suddenly coming from a new or "cold" (ie, recently dormant) IP address, they will take notice of it and immediately begin evaluating the traffic coming from that IP. Since volume is perhaps the most telling factor in the eyes of ISP SPAM filters, it is best to begin sending low to moderate volume, eventually working your way up to larger volumes. This gives the "powers that be" a chance to closely observe your sending habits and the way your customers treat the emails they receive from you."